The anterior cruciate ligament (ACL) is one of the two major ligaments in the knee. It connects the thigh bone to the shin bone in the knee. ACL injuries are a common cause of disability in the knee. In the U.S., 95,000 people get them every year. They are more common in women than men.

The posterior cruciate ligament (PCL) is the second major ligament in the knee connecting the thigh bone to the shin bone in the knee.

The lateral collateral ligament (LCL) connects the thigh bone to the fibula, the smaller bone of the lower leg on the lateral or outer side of the knee.

The medial collateral ligament (MCL) also connects the thigh bone to the shin bone on the medial or in side of the knee.

EMS works to mimic the body's natural muscle movements; signals are sent between the electrode self-conductive pads which are on the garment itself, switching on the nerves that control you muscles and cause them to contract naturally.